Explanation : It is the percentage change in the market value over the period:
Market value at beginning period: (10 * 100) + (40 * 150) + (16 * 200)
= 10,200.
Market value at end of period: (15 * 100) + (38 * 150) + (20 * 200)
= 11,200 Percentage change is (11,200 / 10,200) - 1
= 0.09804 or 9.8 percent with rounding.